Girven, 31, took her job as a police informer so seriously that she listed the city of Tampa as her employer on her Facebook page. A small-time scammer who had been arrested more than 30 times, she helped put away dozens of other criminals and was the go-to source for leads on crime in the violent streets of east Tampa.

But her help didn't come free.

Girven said she could usually count on a hand from friends in the Tampa Police Department — cash for food or gas, care packages when she was in jail, a jump when her car's battery was dead. Her relatives said they traded on Girven's reputation to get out of traffic tickets. A pair of police officers even raised her youngest child.

Now Girven is at the hub of the Police Department's most serious corruption scandal in years. Officers Eric and La Joyce Houston have been fired and are under criminal investigation over tax- and welfare-fraud schemes allegedly carried out with Girven. A federal grand jury has subpoenaed records on a third officer, Rob Fannin, and a former civilian department employee, Tonia Bright, with ties to Girven.

Police Chief Jane Castor said in a statement last week that she has no evidence other department employees were involved. But with each revelation come questions about Girven's singular role as an informer, and whether she might have persuaded others to cross the line between crime-fighter and criminal.

Interviews with Girven — who offered her first public comments on the investigation to the Tampa Bay Times from jail — and her relatives, in addition to police and court records, portray an unprecedented relationship with the department, one that experts say violated basic principles of managing informers.

"I could call anybody. I could just pick up the phone," Girven said. "If — if — I committed tax fraud, it is over 300 Tampa police officers … that I'm close enough to get information from."

Girven, who denies committing tax fraud, is being held without bail at the Falkenburg Road Jail on charges of food-stamp fraud and grand theft. She spoke to the Times twice by telephone.

She said she felt betrayed by a police force she had spent years helping in neighborhoods distrustful of law enforcement. She reserved special criticism for Castor, who she said is scapegoating her and officers close to her.

In June 2011, Girven posed for a photo with the chief at a police event, later posting the picture on Facebook with the caption, Me and my girls this who I run with.

"She keeps saying that I'm a criminal," Girven said last week. "But I wasn't a criminal when she was taking a picture with me. So when did I stop being a criminal?"

Investigation begins

Girven's tightly knotted links with the Police Department began unraveling in October, when Sgt. La Joyce Houston was fired and arrested. Investigators said Houston illegally used Girven's food stamps.

At the time, Castor said she did not believe Eric Houston — La Joyce's husband and a respected homicide detective — was involved with or knew about any acts of fraud.

Further investigation suggested otherwise. In April, Castor called a news conference to announce that Eric Houston, too, had been fired — this time amid a federal grand jury investigation.

A search warrant affidavit filed in federal court late last month outlined that investigation, suggesting that Eric Houston was linked to thousands of fake tax returns. Girven's former home address was used to recoup at least $27,000 in fraudulent refunds, the affidavit stated.

The affidavit revealed that some dead people's identities used for tax fraud matched searches performed in a statewide law enforcement database by both the Houstons and Bright, a community service officer in District 3, covering east Tampa.

Of the three, only La Joyce Houston has been charged. She has pleaded not guilty to state charges of grand theft and food-stamp fraud. Bright was suspended without pay in March, when the department learned she was the target of a federal grand jury investigation, and resigned in April, according to department spokeswoman Laura McElroy.

The federal investigation is ongoing.

"I, along with every member of my agency, was shocked and angered when we uncovered the wrongdoing of La Joyce and Eric Houston," Castor said in a statement to the Times last week. "There's nothing that disappoints police more than a crooked cop."

She added, "We have no evidence or reason to believe that any other officers are involved."

But the scope of alleged criminal conduct connected to Girven — exposed through overlapping state, federal and internal affairs investigations — has not always been clear-cut.

In addition to the files of the Houstons and Bright, the federal grand jury has subpoenaed department records on a fourth employee, Fannin, who is a sworn officer, police say. In November, Fannin was read his Miranda rights and interviewed by Tampa police investigators in the presence of a union attorney about his relationship with Girven.

A transcript of the interview was included in materials on the La Joyce Houston investigation released last month by the Hillsborough State Attorney's Office. It shows Girven alleged that Fannin sent her a care package at the jail in exchange for the use of her food stamps.

Fannin denied the accusation, saying that Girven "hit my Christianity side of me, you know, and I felt bad for her so I sent it."

McElroy said Fannin has been cleared of wrongdoing by department investigators.

Fannin's statements shone a light on Girven's value and track record in the typically secretive world of police informers. "She worked with everybody on that squad giving information" in District 3, he said, estimating that "It's gotta be 30 to at least 50 people" Girven helped put in prison.

'She was one of them'

How did Girven, a small-time career criminal, become such an effective arm of law enforcement?

Girven grew up in the infamous Ponce de Leon Courts housing project in east Tampa. Then as now, the surrounding College Hill neighborhood was plagued by an intractable drug trade and frequent violent crime.

Her relatives and friends said she was an outgoing and sometimes erratic girl, traits she retained as an adult. Prone to brash outbursts — flashing her chest at people from the window of her apartment, fighting on the railroad tracks that bisect east Tampa — she also suffered jags of depression during which she lamented the course her life had taken, those who know her said.

Even as she grew up and found herself often in trouble, Girven enjoyed hanging around the old police substation in College Hill. She said she met Eric Houston, then a beat cop in her neighborhood, when she was about 10.

"She wanted to be a police, but she couldn't because of her record," said her sister Shawn Howard. "She put them on a pedestal, like they couldn't do nothing wrong."

Police have declined to comment on Girven's status as a registered informer, citing confidentiality of the program. The federal affidavit in Eric Houston's case states that Girven "has often worked as a registered confidential informant for the Tampa Police Department."

Rita Girven said her work as an informer began almost casually. "I'd be like, 'Watch this. I bet I can get so-and-so to interview before you can,' " she said, recalling conversations with officers she knew. She said she would usually win these informal bets, facilitating conversations at her home between reluctant witnesses and investigators.

Eventually, she filled out paperwork to register as an informer. When Dontae Morris gunned down two police officers during a traffic stop in 2010, Girven said, she didn't sleep for four days as she worked her connections to try to turn up a lead on the killer's whereabouts.

Surprisingly, Girven said she didn't fear for her safety as a police collaborator. "Everyone knew she was working with the police," said another sister, Deloris Girven. "She wasn't no undercover snitch or nothing like that."

In return, Rita Girven said, she knew she could always go to the police for help paying her electric or phone bills. She said amounts of money up to $150 were available to her on request. Howard said she once saw a police officer respond to a call to jump her sister's car when the battery died.

Relatives say they also reaped some benefits. Deloris Girven said a police officer once let her off when she was caught driving with a suspended license after learning who her sister was.

"She was one of them," Deloris Girven said, "although she didn't have no badge."

A thin line

The use of informers is as old as police work. But in recent years, law enforcement agencies have recognized the need for stricter oversight of their methods, said Jim Wedick, a former FBI special agent and expert on confidential informers.

"They are probably one of the most dangerous categories of people on the street, because under the tacit approval of law enforcement they're allowed to do certain things," Wedick said.

Girven, arrested 34 times in the last 20 years, appears to have led a life uninhibited by her familiarity with police. She has served prison sentences for convictions including grand theft, attempted burglary and credit card fraud, according to state Department of Corrections records.

"She had a hustle. Everybody had a hustle," Howard said. "She had a thing with credit card fraud."

Rita Girven acknowledged her interest in some forms of fraud, but denied she was involved in any tax-fraud schemes. "I was into check fraud and things like that. I never did income tax-return fraud," she said.

She said she was shocked to learn of the investigation of Bright and the Houstons, particularly Eric Houston, who she said could never be seduced into criminal behavior.

"I couldn't even approach him to ask him for something like that," she said. "I feel like that would be disrespecting his integrity. Eric is a cop at all times."

Girven's relationship with the Houstons was exceptionally close — so much so that she placed her youngest child in their care. The police officers became the child's legal guardians.

Perhaps charitable from a personal perspective, such an act showed a serious lapse in professional judgment, said Joseph Pollini, a lecturer at John Jay College of Criminal Justice in New York.

"Never do you go into a personal relationship with an informant," Pollini said. "There's always the potential for something to go wrong. Informants draw a thin line between what's right and what's wrong."

Police who aren't careful risk being led across that line, Pollini said.

"You lose perception of what you're really there to do," he said. "Now, instead of you leading the informant, the informant leads you."

McElroy declined to comment on whether any review of the department's use of informers was taking place because of the events surrounding Girven. She said the Houstons had disclosed that they were caring for Girven's child, and "it was believed to be a good deed that a police couple was taking the child out of the criminal element."

McElroy said the chief's photo with Girven was one of many Castor takes with members of the public, and that Castor did not know Girven personally.

Girven, for her part, said that whatever the outcome of the investigations into her and her patrons on the force, her days of working as an informer are done.

"I retired," she said.

News researcher John Martin and staff writers Patty Ryan and Richard Danielson contributed to this report. Peter Jamison can be reached at pjamison@tampabay.com or (813) 226-3337. Follow him on Twitter @petejamison.